The application of powerful digital signal controller opens a new chapter for power protection systems. Because of their capabilities to process the measuring values digitally
and to perform arithmetic and logical operations using digital signal processing algorithms the numeric protective relays are superior to the traditional digital devices. In
addition, the numeric protective relays offer some additional advantages such as handling complex communication protocols and multiple protective functions.
The numerical relay CSU1 has been designed as a universal three phase over-current and earth fault relay with directional/non-directional characteristics in phase and earth functions.